This invention relates to a multiposition controller for controlling a position of an object to be position-controlled.
Conventionally, when a movable object is to be position-controlled, a motor is rotated in accordance with absolute position information. This will be described as follows with reference to FIG. 1.
Referring to FIG. 1, reference numeral 1 designates a movable contact; numberal 2 designates an object to be controlled; numberal 3 designates a motor and numberal 4 designates a fixed contact; numeral 5 designates a controlling circuit and and numeral 8 designates a motor driving circuit. The movable contact 1 is mechanically coupled to the object 2, which in turn is designed to be driven by the motor 3. More specifically, when the motor rotates, the position of the object moves from a to b, c, d, . . . , n. At these respective positions corresponding fixed contacts 4 are connected to the movable contact 1.
Now, assuming that the object 2 is positioned at a position c and is to be moved to a position a, the information that the object 2 is at the position c is obtained from an input signal to the controlling circuit 5. So, the controlling circuit 5 outputs a control signal to the motor driving circuit 8 for causing the motor 3 to rotate so as to move the object to the position a. When the object 2 arrives at the position a, the motor 3 is stopped. At an initial state where the movable contact 1 is connected to the fixed contact 4, such movement can be achieved. On the other hand, at an initial state where the movable contact is not connected to any one of the fixed contacts 4, the motor 3 is first rotated in either direction so that the movable contact 1 is connected to one of the fixed contacts 4 before the above described movement of the object to the position a can be achieved. However, in this conventional case, the required number of fixed contacts and connecting lines between the fixed contacts and the controlling circuit 5 corresponds to the number of such multiple positions among which the object is to be moved. Furthermore, when such multiple positions are increased in number, the numbers of fixed contacts 4, connecting, lines and input terminals of the controlling circuit 5 must be increased likewise.